linux-kernel - Re: [PATCH v5 1/3] nvmem: dt: document SNVS LPGPR binding

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Date:   Mon, 19 Jun 2017 08:06:29 +0200
From:   Oleksij Rempel <ore@...gutronix.de>
To:     Stefan Wahren <stefan.wahren@...e.com>
Cc:     Oleksij Rempel <o.rempel@...gutronix.de>,
        devicetree@...r.kernel.org, kernel@...gutronix.de,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Mark Rutland <mark.rutland@....com>,
        Maxime Ripard <maxime.ripard@...e-electrons.com>,
        Rob Herring <robh+dt@...nel.org>,
        Shawn Guo <shawnguo@...nel.org>,
        Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
Subject: Re: [PATCH v5 1/3] nvmem: dt: document SNVS LPGPR binding

On Fri, Jun 09, 2017 at 04:59:00PM +0200, Stefan Wahren wrote:
Hi Stefan,

> Hi Oleksij,
> 
> Am 09.06.2017 um 14:57 schrieb Oleksij Rempel:
> > Documentation bindings for the Low Power General Purpose Register
> > available on i.MX6 SoCs in the Secure Non-Volatile Storage.
> >
> > Signed-off-by: Oleksij Rempel <o.rempel@...gutronix.de>
> > ---
> >  .../devicetree/bindings/nvmem/snvs-lpgpr.txt          | 19 +++++++++++++++++++
> >  1 file changed, 19 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/nvmem/snvs-lpgpr.txt
> >
> > diff --git a/Documentation/devicetree/bindings/nvmem/snvs-lpgpr.txt b/Documentation/devicetree/bindings/nvmem/snvs-lpgpr.txt
> > new file mode 100644
> > index 000000000000..21910fb3159f
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/nvmem/snvs-lpgpr.txt
> > @@ -0,0 +1,19 @@
> > +Device tree bindings for Low Power General Purpose Register found in i.MX6Q/D
> > +Secure Non-Volatile Storage.
> > +
> > +This DT node should be represented as a sub-node of a "syscon",
> > +"simple-mfd" node.
> > +
> > +Required properties:
> > +- compatible: should be:
> > +	"fsl,imx6q-snvs-lpgpr" for Freescale i.MX6Q/D/DL/S
> > +
> > +Example:
> > +snvs: snvs@...cc000 {
> > +	compatible = "fsl,sec-v4.0-mon", "syscon", "simple-mfd";
> > +	reg = <0x020cc000 0x4000>;
> > +
> > +	snvs_lpgpr: snvs-lpgpr {
> > +		compatible = "fsl,imx6q-snvs-lpgpr";
> 
> according to the reference manual at least the clock "lp_ipg_clk_s" is
> required for register R/W access.
> So it should be added to the binding and enabled by the driver.

Hm...
Non of current SNVS drives use, set or defines *_ipg_clk_s. I can't find
in the docs how can I control this clocks.
lp_ipg_clk_s and hp_ipg_clk_s depend on ipg_clk_root, which seems to be
not gated. So, it is always on. Or do I miss something.

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